Safety studies indicate over 234,000 bathroom injuries each year, of which 81 percent occurred because of falls in the bathroom. See Bakalar, “Watch Your Step While Washing Up”, New York Times, Aug. 15, 2011, citing CDC Centers for Disease Control and Prevention, “Nonfatal Bathroom Injuries Among Persons Aged >15 Years, United States, 2008”, Morbidity and Mortality Weekly Report (MMWR), 60 (22); 729-733, Jun. 10, 2011. Of these injuries, more than one third happen while bathing or showing. The Center for Disease Controls (CDC) estimates that 9.8 percent of all bathroom injuries specifically occur when getting out of a bathtub, which equals at least 22,932 injuries.
Applicants believe that injuries while getting out of a bathtub occur because of the wide straddling of the bather's legs when exiting a bathtub. The horizontal component force Fs that arises from this arrangement is 0.306 W or almost 31% of the weight of the person. This horizontal component must be resisted by the frictional force between the ball of the anchor foot and the tub (or a tub mat). Several items affect the local coefficient of friction between foot and tub, or foot and mat and mat to tub. Water, and especially soapy water, is a good lubricant and dramatically reduces the coefficient of friction. If the widely straddled anchor foot slips, the bather's weight is subject to horizontal sideways force and prone to dangerous falls while attempting to exit the bathtub.
In addition to the aforementioned safety issues, when viewed in crossection from an end, conventional prior art bathtubs have limited interior bathing space by virtue of the fact that the upper apron deck provided for sliding glass doors is usually three or more inches in top width, which narrows considerably the interior bathing or showering space or volume within the conventional bathtub. Additionally, for symmetry purposes, a similar opposite wall abutting top edge is also typically three or more inches in top width, thereby further limiting the space or volume within the bathtub. Typical residential bathrooms generally have a limited rectangular footprint area of 60 inches by 30 or 32 inches within which to locate a bathtub and shower installation. So losing 1, 2, 3 or 4 inches in width results in a significant reduction in the overall internal space or volume within a typical bathtub.
Among known prior art patents includes U.S. Pat. No. 2,431,475 of Gruen, which discloses the elimination of a front bathtub apron wall and the creation of an apron effect, by providing a front wall having an upper edge wall fanning outward, both inside the tub and outwards from the front of the tub, to prevent water from splashing out of the bathtub.
US Patent Application 2011/0167728 of Alelov discloses an “Expandable Side Enclosure for Bathtubs/Showers”, to provide a solution to prevent arm movement restrictions caused to bathers in bathtubs and/or showers due to the lack of free body and limb movement in baths with standard enclosures. While Alelov provides outwardly extended bay-type windows in the sliding glass doors, which are at standing arm height, to provide more movement of the arms during a shower. However, Alelov does not increase the internal volume of the bathtub itself.
U.S. Pat. No. 1,811,896 of Ross discloses a circular topped truncated conical water basin/bowl/tub with an inwardly inverted anti-splash lip/flange. However, Ross cannot be installed in a typical rectangular bathtub footprint in a residential bathroom.
U.S. Design Pat. D619,685 of Hoernig discloses a shower and tub with a “flip up out of the way” apron deck, to expand the interior space of the bathtub. However, Hoernig requires moving parts and hinges, which are complicated and detrimental in a high humidity bathtub environment.
U.S. Design Pat. Des. 335,701 of Zaccui discloses a bathtub which increases interior space by having bulging outwardly extending side walls. However, the bulging sides of Zaccui '701 prevents its installation within a standard bathtub area.
These known prior art devices do not maximize internal bathtub/shower stall space within the predetermined confines of typical residential bathroom space dimensions. The use of the an inwardly extending only cantilevered top apron edge in the present invention for an expanded space bathtub, where the rear wall has no apron edge, would be discouraged, if not clearly taught away from the prior art patents.
Therefore, the use of a bathtub with both an inwardly extending apron deck and an expanded footprint and volume for the bathtub, as in Applicants' present invention, in conjunction with the spatial confines of a rectangular bathtub installation area of a residential bathroom, is not only not suggested, but would be discouraged or taught away by the designs known from the conventional arts.